Note: Descriptions are shown in the official language in which they were submitted.
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SYNTHETIC METALWORKING FLUI~
This application is a continuation-in-part of U.S.
Application Ser. No. 287,963, filed 12/21/88.
The present invention relates to metalworking fluids
and more particularly a synthetic metalworking fluid which
provides e~cellent lubrication and cooling for both hard and
soft metals and is relatively bioresistant.
BACKGROUND CF THE INVENTIQN
In most industrial metal working operations, a
metalworking fluid is employed. Metalworking fluids act both
as a coolant to maintain the temperature of the metal surfaces
within a desired range and as a lubricant to lubricate the
interface of the tool and metal. The cooling effect of the
metalworking fluid adds considerable life to the cutting
tools, such as drill bits, metal formers, etc., and also tends
to prevent the warping or distortion of the metal. The
lubricating properties, on the other hand, reduce the friction
between the cutting tool and the metal, thereby reducing the
power requirement of the machinery.
There are four types of metalworking fluids: ¦
straight oils, soluble oils, semi-synthetics and synthetics.
Straight oils, which include mineral and vegetable oils,
provide e~cellent lubricating properties but only minimal
cooling. Soluble oils, i.e. emulsions of oil in water,
provide both lubricity and cooling, and perform well on both
hard metals, such as titanium and steel, and soft metals, such
as aluminum. However, soluble oils are usually subject to
rapid biodegradation and impaired lubricity after repeated
use. Semi-synthetics, i.e. water solutions with smaller
amounts oil microemulsified, and synthetics, i~C~
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non-petroleum based emulsions or solutions provide improved
lubricity and cooling, can be filtered, and can generally be
used for much longer periods of time than soluble oils.
However, neither synthetics nor semi-synthetics, free of
chlorine, sul~ur or phosphorous, have been successfully used
on difficult machining operations, e.g. tapping of both hard
and sot metals. Prior art synthetics have used chlorine,
sulfur or phosphorus as extreme pressure additives in order to
machine hard metals. These additives create a hazard to the
environment, and chlorine can cause hydrogen embrittlement
(stress cracking). Also, when cutting differen~ metals it has
been necessary to change metalworking fluids during the
manufacturing process, increasing production time and causing
disposal problems.
Soluble oils containing chlorine, sulfur or
phosphorous extreme pressure additives have been used when a
manufacturing process requires the working of two or more
metals of significantly different hardnesses. However,
soluble oils have several drawbacks. First, a single soluble
oil may not be suitable for all metals in severe deformation
processes such as tapping. Secondly, soluble oils have a ¦
typical useful life of 2-3 weeks, whereas synthetic fluids may
be used for 12 months or more. Also, soluble oils present a
disposal problem due to their petroleum base. If chlorine is
present, an even greater disposal problem e~ists.
The present invention provides a synthetic fluid,
free of chlorine, sulfur and phosphorous, without the
shortcomings of soluble oils, wh;ch may be used as a
metalworking fluid when working two or more metals of
different hardnesses. The metalworking fluid of the present
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invention provides good lubrication and cooling t~ both hard
and soft metals, allowing a ~ingle fluid to be used for both
types of metal even in severe applications.
SUMMARY AND OBJECTS OF THE INVENTION
The present invention relates to a metalworking fluid
containing a polybutene such as an isobutylene-butene
copolymer or polyisobutylene; and a polyether glycol having a
carbo~ylate functionality. In one preferred embodiment, the
polybutene is a copolymer composed of 95-100% by weight
mono-olefins and 0-5% by weight isoparaffins. The
metalworking fluid may or may not be diluted with water to
form a micro-emulsion.
It is an object of the present invention to provide a
metalworking fluid comprisin~ an isobutylene-butene copolymer,
composed of 95-100% by weight mono-olefins and 0-5~ by weight
isoparaffins; a polyether glycol having a carboxylate
functionality; and an emulsifier capa~le of forming a stable
micro-emulsion.
Another object of the present invention is to provide
a metalworking fluid comprised of an isobutylene-butene
copolymer, a polyether glycol having a carbo~ylate
functionality, a corrosion inhibitor and a defoamer.
A further object of the present invention is to
provide a metalworking fluid that provides lubrication and
cooling during the working of both hard and soft metals.
Yet another object of the present invention is to
provide a metalworking fluid which prevents the buildup of
residue on tooling and the metal being worked.
An additional object of the present invention is to
provide a water dilutable, micro-emulsion metalworking fluid
comprising from about 2 to about 50 parts by weight of an
isobutylene-butene copolymer or polyisobutylene, and from
about 2 to about 50 parts by weight of a polyether glycol
having a carboxylate functionality.
An object of the present invention is to provide a
metalwork;ng process comprising the steps of forming a
metalworking fluid of an isobutylene-butene copolymer or
polyisobutylene; and a polyether glycol having a carboxylate
functionality, applying the metalworking fluid to a metal to
be worked and working the metal.
Another object of the present invention is to provide
a metalworking fluid comprised of a blend of an
isobutylene-butene copolymer, or polyisobutylene, a polyether
glycol having a carbo~ylate functionality and an emulsifier,
the blend being diluted in a volume of water such that the
blend comprises from about 0% to about 95% by volume of the
total volume of blend and water.
An object of this invention is to provide a
metalworking fluid comprising an emulsi iable blend of from
about 2 to about 50 parts by weight of an isobutylene-butene
copolymer, composed of about 95-100% by weight of one or more
mono-olefins and about 0-5% by weight of one or more
isoparaffins; from about ~ to about 50 parts by weight of a
polyether glycol having a carbo~ylate functionality; and from
about 5 to about 160 parts by weight of one or more
emulsifiers.
l.
An additional object of the invention is to provide a
metalworking fluid comprising from about 2 to about 50 parts
by weight of a polybutene and from about 2 to about ~0 parts
by weight of a polyether glycol having a carbosylate
functionality.
These and other objects will be readily discernable
to one skilled in the art from the following preferred
embodiments and appended claims.
DETA~LED DESCRIPTION OF TH~ PREFERRED EMBODIMENTS
The present invention overcomes the shortcomings of
prior metalworking fluids by providing a synthetic
metalworking fluid which is useful in working both hard and
soft metals.
The metalworking fluid of the present invention
contains two major constituents, a polybutene selected from
the group consisting of isobutylene-butene copolymers and
polyisobutylenes~ to provide the lubricity needed for working
soft metals, and a polyether glycol having a carboxylate
functionality as an e~treme pressure additive for working hard
metals. It has been found that this synergistic blend may be
used to machine both hard and soft metals. The blend also
une~pectedly provides lubricity superior to that obtained when
polybutenes are used alone, and e~treme pressure properties
superior to those obtained when polyether glycols are used
alone. One or more emulsifiers may be added to the polybutene
and the polyether glycol when the concentrate is to be
emulsified in water. Other common metalworking fluid
constituents may also be added, if desired.
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The fluid is made in concentrate (neat) form, i.e.
without the addition of water. The fluid may be used in its
neat form or it may be diluted to a lesser concentration with
water, if so desired.
The concentrate will preferably have a pH of from
about 8 to about 10.5, more preferably from about 8.5 to about
9.5.
The isobutylene-butene copolymer used in one
embodiment of the present invention is composed of about 95%
to 100% by weight mono-olefins and about 0% to 5% by weight
isoparaffins. Mono-olefins are a class of unsaturated
aliphatic hydrocarbons with one double bond, obtained by
cracking petroleurn fractions at high temperatures.
Isoparaffins are a class of aliphatic hydrocarbons
characterized by a straight or branched carbon chain, and have
the generic formula CNH2n+2. Various grades of such a
copolymer are commercially available from the Amoco
Corporation and are sold under the tradename INDOPOL~. Any of
these grades may be used in the present invention~ but
preferably those with a viscosity less than 5000 SUS (measured
at 100F).
One e~ample of a suitable isobutylene-butene
copolymer has an average molecular weight of 563, a viscosity
of 2441 SUS at 100F, and a flash point of 141C, and is sold
under the tradename ~Amoco Polybutene H-15~. The amount of
copolymer used in the present invention can range from about 1
part by weight to about 50 parts by weight. Preferably, the
amount used is from about 2 parts by weight to about 36 parts
by weight.
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The term polybutene refers to either a
polyisobutylene which is essentially pure, or the
isobutylene-butene copolymer described above which may contain
up to about 5~ of other polymers, such as l-butene and
2-butene. The isobutylene-butene copolymer is preferred, as
it is less susceptible to crystallization at low temperatures,
but similar properties can be obtained using the 99+~
polyisobutylene. Mixtures of polyisobutylene and the
isobutylene-butene copolymsr may also be used.
The isobutylene-butene copolymer, or polyisobutylene,
is desired because it provides the lubricity ne~ded to obtain
a good surface finish on soft metals such as aluminum.
The second constituent of the metalworking fluid is a
polyether glycol having a carboxylate functionality. The
polyether glycol having this structure provides additional
lubricating properties to the metalworking fluid, and acts as
an extreme pressure additive which reduces tool wear when
machining hard metals such as titanium. Thus it is possible
to machine hard metals without the use of traditional
chlorine, sulfur or phosphorus e~treme pressure additives,
eliminating the hydrogen embrittlement and disposal problems
caused by these additives. Suitable polyether glycols are
commercially available from the Olin Corporation~ under the
trademark, POLY~G~.
One e~ample of a suitable polyether glycol is the
proprietary polyoxyalkylene ylycol sold by Olin Corporation
under the tradename POLY-G~ MLB-lOX~ This polyo2yalkylene
glycol has a viscosity of 587 SUS (at 100F) and a specific
gravity of 1.066 at 25C. The carbo~ylate functionality of
this polyoxyalkylene glycol is acidic in nature.
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The amount of polyether glycol used in the present
invention can range from about 2 parts by weight to about 50
parts by weight. Preferably, the amount used is from about 5
parts by weight to about 36 parts by weight.
A third constituent of the metalworking fluid, if
desired, may be one or more emulsifiers. Any oil-in-water
emulsifier may be used in the invention, alone or in
combination with other emulsifiers.
Examples of suitable emulsifiers that may be used in
the present invention include but are not limited to tall oil
fatty acids, petroleum sulfonates, fatty acid amines, fatty
acid alkanolamides and nonionic, cationic, anionic or
amphoteric surfactants.
The selected emulsifiers should completely emulsify
the other constituents of the concentrate when mixed with
water. The emulsifiers should also be capahle of maintaining
a stable emulsion during use.
The amount of emulsifier used in the concentrate is
generally from about 5 parts b~ weiqht to about 160 parts by
weight.
Other conventional metalworking fluid additives may
be added so long as they do not adversely affect the emulsion
stability or lubricity of the fluid. Such additives include
corrosion inhibitors, defoamers, biocides, surfactants,
azeotropes, colorants or dyes and pH buffering agents.
Examples of suitable corrosion inhibitors include,
but are not limited to, amine carboxylates and amine borate
esters. Other suitable corrosion inhibitors would be obvious
to o ~killed in the a~t and a e conullercially a~ailable.
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The amount of corrosion inhibitor is generally from
about .1 part by weight to about 20 parts by weight, and
preferably from about .1 parts by weight to about 15 parts by
weight in the concentrate.
Suitable defoamers may be used in the present
invention. Such defoamers are generally proprietary products
and are known only by their commercial trade names. Suitable,
preferably organic, defoamers for use in the present invention
include TROYKYD~ D666, a proprietary blend available from Troy
Chemical, and Foam Ban MS-455 from Ultra Additives. Other
suitable defoamers would be obvious to one skilled in the art.
The amount of defoamer is generally from about 0.25
parts by weight to about 10 parts by weight, and preferably
from about 0.5 parts by weight to about 5 parts by weight.
The concentrate may be formed in any conventional
manner such as 3dding all of the ingredients simultaneously
and mixing them until a completely blended liquid is formed.
However, it is preferred to first add the isobutylene-butene
copoly~er, or polyisobutylene, to a large mixer, then slowly
add the one or more emulsifiers and then the corrosion
inhibiting agent and polyether glycol, mi~ing well after each
addition. Lastly, any other ingredients such as a defoamer
and dye are added and thoroughly mi~ed into a homogeneous,
stable blend. If desired, small amounts of water, may be
added subsequent to mixin~. The concentrate is then decanted
into containers for storage and shipment.
The metalworking fluid may be used in its neat form
i.e., as a concentrate or it may be diluted.
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Preferably, the metalworking fluid is diluted with
water such that the amount of concentrate is from about 1% to
50% by volume of the total volume of the water and
concentrate. However, in applications where water cannot be
tolerated, a 100~ solids concentrate can be used.
For example, where lubricity properties are most
desired, less water is used so that there is more concentrate
present. When cooling properties are most desired, the volume
of water is greater than the volume of concentrate.
Generally, where lubricity is primarily required, the amount
of water used is about 50% by total volume. Where cooling is
primarily required, the amount of water is from about 80% to
99% by total volume.
The metalworking fluid is useful on a variety of
metals including but not limited to steel, iron, aluminum,
copper, titanium, nickel and alloys thereof.
EXAMPLE 1
A metalworking fluid concentrate of the following
formula was mi~ed together:
4.5 parts by weight of an isobutylene-butene
copol~ner;
- 6.0 parts by weight of a tall oil fatty acid low
rosin emulsifier;
12.6 parts by weight of a petroleum sulfonate fatty
acid amine blend emulsifier;
8.3 parts by weight of a fatty acid alkanolamide
emulsifier;
7.5 parts by weight of polyoxyalkylene glycol, Olin
Chemicals POLY-G~ MLB-lOX;
0.1 parts by weight of a surfactant,
1.5 parts by weight of an amine carboxylate corrosion
inhibitor;
1.3 parts by weight of an amine borate ester
corrosion inhibitor;
1.0 parts by weight of a sodium salt of tolyltriazole
corrosion inhibitor;
0.2 parts by weight of a citrus fragrance;
1.5 parts by weight of a glycol ether;
3.0 parts by weight of a biocide;
0.5 parts by weight of triethanolamine;
0.5 part by weight of a defoamer, Troy Chemicals
Troykyd~ D666; 0.5 of a second defoamer, Foam Ban MS-455 from
Ultra Additives and, 0.06 part by weight of a blue dye.
51.0 deionized water (optional).
The fluid of E~ample 1 was used to machine hydraulic
valve bodies from 2024 and 356 cast aluminums and titanium
using a carbide tool. A straight oil was used side by side
with the fluid of Example 1 for compar;son. Results were as
follows:
Fluid of
Coolan~ Typ~ ~traiqh~ Oil E~ample 1
Concentration 100~ 11% co~centration
in water
Sump Li f e 2 Months > 4 Months
Parts/Tool
Milling 500 1000+
Reaming 135 475+
Drilling 200 9oo+
Speed (SFM)
Milling 60 600
Reaming 30 490
Drilling 100 600-800
Finish (RMS)
Reaming 20-30 8-16
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The metalworking fluid of Example 1 was usable for
more than twice as long as the straight oil. This is due both
to the greater thermal stability of the fluid of Example 1 and
to its reduced susceptibility to contamination by metal
fines. The number of parts which could be machined with a
given tool was greatly increased. Higher speeds were also
obtainable and the surface finish was improved.
While this invention has been discussed in the light
of its preferred embodiments, i,e. as a metalworking fluid for
the cutting of hard and soft metals, it is by no means meant
to be so limited. The metalworking fluid of this invention
may be used in any metalworking operation where its properties
would be useful. Examples of such metalworking operations
include but are not limited to tapping, grinding, milling and
forming.
Further, while this invention has been described with
reference to its preferred embodiments, other embodiments can
achieve the same results. Yariations and modifications of the
present invention will be obvious to those skiiled in the art
and it is intended to cover in the appended claims all such
modifications and equivalents as fall within the true spirit
and scope this invention.
2402P
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